Policy Implications of the New Teacher Value-Added Research
cross-posted at The Nation
Last month, economists at Harvard and Columbia released the largest-ever study of teachers’ “value-added” ratings—a controversial mathematical technique that measures a teacher’s effectiveness by looking at the change in his students’ standardized test scores from one year to the next, while controlling for student demographic traits like poverty and race.
Raj Chetty, John Friedman, and Jonah Rockoff analyzed the test scores and family tax returns of 2.5 million Americans over a twenty-year period, from 1989 to 2009. The team concluded that students who have teachers with high value-added ratings are more likely to attend college and earn higher incomes, and are less likely to